The $463 million, three-year-old fund bets primarily on debt instruments such as high yield bonds, senior loans, and convertible securities, a substantial portion of which may be rated below investment-grade. It sports an expense ratio of 82 basis points and is managed by Gunther Stein and Jenny Rhee.

“For income-seeking investors concerned about the dual risks that rising rates and a low yield environment present to their portfolio, we are pleased that our fund has achieved this rating from Morningstar and can provide an important option to address their concerns,” stated Margo Cook, executive vice president, Nuveen Investments.

The Nuveen Investments family of mutual funds manage some $50 billion in nearly 100 mutual funds as of Mach 31.